Envelope



Nox/.27,1945

w. E. swlF-r ENVELOPE Filed Jan. 2, 1945 FIG. l.

FIG. 3.

www mewm N YEF. v A md W@ wm Patented Nov. 27, 1945 UNITED STATES PATENT OFFICE ENVELOPE Willard E. Swift, Worcester, Mass., assigner to United States Envelope Company, Springfield, Mass., a corporation ofMaine Application January 2, 1943, Serial No. '471,114

' preciable overlap of the side flap 2; in the en- 2 Claims.

The present invention relates to envelopes of the type in which closure is effected by means of the insertion of an integral tongue through registering perforations provided in overlying flap and body portions of the envelope, whereby the ap is locked in position by the inserted tongue.

Such an envelope is exemplied by Trenchard Patent No. 1,519,567, dated December 16, 1924, in accordance with which the locking tongue, by a transverse fold back of its material, is made of double thickness, to increase the stiffness thereof.

I'he envelope of my invention provides an improved construction for this integral doublethickness locking tongue, by which to make it far more durable in its zones or portions of greatest wear, and far less liable to disintegration by the parting or separation of its two constituent plies of envelope material, under the iiexings involved in repeated openings and closings of the envelope. In this latter respect my improved envelope provides a satisfactory substitute for various types of metallic fastener envelopes no longer available during the present emergency.

The above and other advantageous features of the invention will hereinafter more fully appear from the following description, considered in connection with the accompanying drawing, in which- Fig. 1 is a plan view showing the blank from which is made the envelope of my invention.

Fig. 2 is a rear view of the completed envelope, with the closure flap in open position.

Fig. 3 is a vertical sectional view through the envelope, with the flap locked in closed position.

Referring iirst to Fig. l, the blank from which my improved envelope is made comprises a rectangular bo'dy portion I as inclosed by dot and dash lines, the said body portion constituting the envelopes front wall; projecting from said body portion I are side flaps 2 and 3, a bottom flap 4, and a closure Hap 5. In cutting the blank, the side flap Z and closure iiap 5 are provided with slots 6 and l, respectively, so positioned that when the flap 5 is folded over to close the completed envelope of Fig. 2, its slot 'I will register with the slot 6 provided in the envelopes back wall by the side flap 2. The flap 5 is preferably formed with an extension 8 beyond a fold line 9, and this extension provides a slot I0 for registration with the slot 'I when the extension is folded over along the line 9, as shown in Fig. 2.

In the rear wall of my improved envelope as shown by Fig. 2, the side flap 3 makes an apvelope blank (Fig. 1), the flap 3 is cut to a width considerably greater than needed for this overlap, such extra width being provided by a lateral extension 3a, beyond the line I4, Fig. 1. In-

l' Wardly of said line I4, the ap 3 is formed with a slit II opening downwardly from the upper edge of said flap, which edge beyond said slit is preferably constituted by converging lines I2 and I3 which meet at an angle that is bisected by the line I4.

In making my improved envelope from the blank of Fig. l, that portion 3a of the ap 3 beyond the line I4 is folded over on said line to make the flap of double thickness beyond the slit I I, the two thicknesses or plies of the flap being secured together by suitable adhesive I5 applied to the flap before the fold is made. The extension 8 of closure flap 5 is similarly folded along line 9 to bring the perforations 'I and III into registration, with the overlying portions of the flap being secured together by previouslyapplied adhesive IB. Following this initial folding and adhesion which gives double thickness to portions of the flaps 3 and 5, the blank is conventionally folded and its overlapping flaps adhered to form the completed envelope of Fig. 2; that is to say, the rst fold-over is of ap 2, followed by a fold-over of ap 3 which overlaps at its outer edge (the fold I4) upon a portion of flap 2portons of said overlapping areas being united in this operation by an area of suitable adhesive I'I (Fig. 1) to incorporate said edge I4 in a central back Wall seam, whose upper terminal is at or below the level of the bottom of slot II. Then the flap 4 is folded over and secured by adhesive I8 to the lower edges of the flaps 2 and 3, to form the envelopes bottom closure, and

to complete the envelope pocket.

Thus in the completed envelope the upper portion of flap 3, between slit II and edge I4, is left unsecured to ap 2 and forms a double-thickness locking tongue I9 for cooperation with the slots E and 'I of back wall and closure ap, respectively. In so using the envelope after insertion therein of the contents, the tongue I9 is flexed back, and the closure iiap 5 is folded down, thereby bringing its slots 'I and I into register with the rear wall -slot Ii. In order to lock the flap 5 in closed position, -the tongue I9 is seized and flexed sufficiently to enter its upper edge in the registered slots 6, 'I and I0, so as to lie behind the rear wall ap 2 above said slots, as is evident from a consideration of Fig. 3.

The above described construction of a doublethickness locking tongue I9 is particularly effective in enabling said tongue to withstand the wear and abuse involved in its repeated flexures and its back and forth movements through the slots, in the frequent locking and unlocking of the closure flap 5. Repeated flexures of such a two-ply element invariably tend to destroy the adhesive connection at the base of the tongue (the zone of maximum ilexure) between the layers of material, but in my envelope the tongue element suffers no actual separation or appreciable loss of stiffness from such disintegration of the adhesive bond, because in the completed envelope the flap extension 3a which provides the tongues reinforcement is not exposed on the outside of the envelope, but is an underneath interior fold, so arranged as to remain in, tonguestiffening position despite any loosening of the adhesive connection. It is to be noted further that customary manipulations of such a tongue, for insertions into and withdrawals from the slots of the back wall and closure flap, involve rubbing contact between the tongues righthand longitudinal edge and the end portions of said slots; but in my improved reinforced tongue construction, the fact that this edge is constituted by a fold of the material rather than by the individual edges of two layers of material, makes for far greater resistance to fraying of said edge under repeated rubbings against the end portions of said slots. In addition, this tongue reinforcement by a longitudinal rather than a transverse fold gives opportunity, without waste of material, to provide said tongue at its end with a point 20, for greater ease of entering it in the registered slots of closure flap and rear wall--this resulting from the angle between edge portions I2 and I3 of flap 3a, which is bisected by the fold line I4 as previously described.

I claim:

1. An envelope having a pocket portion and a slotted closure flap, said pocket portion having a front wall and a rear wall, the latter comprising two opposite side flaps and a bottom flap, said three aps being folded inwardly and adhesively connected to each other in mutually overlapping areas, one of said side flaps having a slot with which registers the slot of said closure flap when the latter is' 'folded down to pocket-closing position, the second side flap having a slit extending inwardly from its upper edge to provide an integral tongue for insertion through the so-registered slots, and a reinforcement for said tongue, comprising an integral lateral extension on said second side ap, said extension being folded under betweensaid two side flaps and adhered to said tongue to double its thickness, the line of said fold running longitudinallyv of said tongue and constituting one of its longitudinal edges.

2. An envelope having a pocket portion and a slotted closure flap, said pocket portion having a front wall and a rear Wall, the latter comprising two opposite side flaps and a bottom flap, said three flaps being folded inwardly and adhesively connected to each other in mutually overlapping areas, one of said sideA flaps having a slot with which registers the slot of said closure flap when the latter is folded down to pocket-closing position, the second side flap having a slit extending inwardly from its upper edge to form an integral tongue for insertion through the so-registered slots, and a reinforcement for said tongue comprising an integral lateral extension of said second side flap, said extension being folded upon and adhesively secured to said tongue to double its thickness, the line of said fold running longitudinally of said tongue and constituting one of its longitudinal edges, the upper edges of said second side flap and its lateral extension standing at an angle which is bisected by said line of fold, to give said tongue a point at one of its corners.

WILLARD E. SWIFT. 

